1. Field of the Invention
The present invention relates to a compositional analysis method for analyzing a composition in an image, or an image apparatus implementing this compositional analysis method. The compositional analysis method may be also implemented on a structural analysis program recorded in a computer-readable recording medium. Preferred examples of the image apparatus include a digital camera, a digital video camera, or image display devices such as a digital signage or a photoframe.
2. Description of the Related Art
Composition is important for an image. The composition is also known as arrangement, disposition, layout, proportion, or balance.
Several techniques for providing preferred compositions in the image have been proposed.
For example, the image recording and editing apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2002-218306 incorporates a template expressing a preferred composition preliminarily in the apparatus. This image recording and editing apparatus extracts contour line information of a subject by image processing from an acquired image, calculates the differential portion of the contour line information from the template, and drives the zoom lens so as to minimize the differential portion. According to this technique, the subject of a human figure or the like can be imaged in a size matched well to the template. As a result, an image of a pleasing composition is often obtained.
On the other hand, hitherto, the golden ratio is known as an aesthetically pleasing ratio. The golden ratio is a ratio of 1: (1+√{square root over (5)})/2, and its approximate value is 1:1.618, or about 5:8. A Fibonacci sequence of numbers is a sequence defined by F1=1, F2=1, Fn+2=Fn+Fn+1, and it is known that the ratio of two adjacent terms in a Fibonacci sequence of numbers converges on the golden ratio.
As often seen among Western paintings in the Renaissance period, when determining the composition or the proportion, the geometrical configuration represented by the golden ratio has been considered as an important element.
Another example of an aesthetically pleasing ratio is the silver ratio. The silver ratio refers to either 1: (1+√{square root over (2)}) or 1:√{square root over (2)}. The silver ratio is excellent aesthetically, and also has an advantage that halving a rectangular shape having the silver ratio longitudinally produces a similar shape to the original rectangle. Mainly for this reason, a representative application of the silver ratio is found in the paper format size (A4, A3, etc.).
When determining a preferred ratio, other viewpoints than the aesthetic aspect are also known. For example, when an acquired image is to be reproduced by a high-definition television, the aspect ratio of the high-definition television must be taken into consideration when image acquisition, and it is preferred that the subject be located in a good balance within the image acquiring range of this aspect ratio.